Many machine components are used in relatively demanding operating environments which can lead to damage or wear over time. The relatively high temperatures and pressures associated with many turbine applications are one example of a relatively demanding operating environment. Turbine wheels used in connection with turbochargers commonly develop blade damage after a certain period of service, depending upon the particular service conditions.
When an internal combustion engine is started or stopped, many of its components tend to heat or cool, respectively, relatively rapidly. Differing rates of expansion or contraction among components of the internal combustion engine can generate many relatively small particles which dislodge from the components. In an exhaust system, such particles may become airborne and impact blades of a turbocharger's turbine wheel relatively hard, adding to the already demanding nature of the environment. Micro-cracks, pits, chips and other forms of blade damage can occur due to impacts with particles, or for other reasons in a conventional turbocharger. When an associated internal combustion engine or certain of its components are removed from service, such as for remanufacturing, damaged turbine wheels are typically scrapped. Since turbine wheels are relatively highly machined and precisely designed components, the economic downside to wholesale scrapping of turbine wheels will be readily apparent.
A number of strategies for repairing bladed components, such as turbine vanes used in gas turbine engines, have been proposed over the years. United States Patent Application Publication No. 2006/0049153 to Cahoon et al. (“Cahoon”) is directed to a dual feed laser welding system which is purportedly applicable to gas turbine engine components for automated welding repairs. Cahoon proposes feeding a filler material through a wire feeder, then melting the filler material via a laser and permitting the melted filler material to be deposited on a component to be repaired. While Cahoon may be applicable in certain instances, the strategy is not without drawbacks. Positioning the filler material wire within a laser beam, elevated from the component to be repaired, tends to reflect a certain amount of the laser light by way of the typically shiny outer surface of the wire. In addition, the melted filler material is apparently dropped or spattered onto the component to be repaired, which would tend to waste material and reduce the overall precision, quality and consistency of the welding process. Various proposals for powder spray welding and other strategies suffer from similar drawbacks with regard to wasting material and consuming laser energy.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.